Classification of upper tract urothelial preneoplastic and neoplastic lesions mirrors that of the urinary bladder, with all lesions of the bladder urothelium being possible in the upper tract and vice versa.
There are three major groups of non-invasive urothelial neoplasms: flat, papillary, and inverted. These three groups share a similar morphological spectrum of intraurothelial changes, ranging from hyperplasia to dysplasia to carcinoma in situ. However, they differ in terms of architectural growth pattern compared to the surrounding non-neoplastic mucosal surface. Infiltrating urothelial carcinoma is defined as a urothelial tumor that invades beyond the basement membrane. Unlike in non-invasive papillary urothelial neoplasms (pTa), the role of histologic grade in pT1 and higher stage tumors has been suggested to be of only relative importance. The vast majority of tumors of the upper urinary tract are urothelial carcinoma. More commonly seen, however, are foci of squamous differentiation and, less frequently, glandular differentiation. Pure urothelial carcinomas also display a wide range of variant morphologies, and recognition of these morphologies is important for diagnosis, classification, and prognosis.
Written by:
Mazzucchelli R, Scarpelli M, Galosi AB, Di Primio R, Lopez-Beltran A, Cheng L, Montironi R. Are you the author?
Section of Pathological Anatomy, Polytechnic University of the Marche Region, School of Medicine, United Hospitals, Ancona, Italy; Division of Urology, Murri General Hospital, Fermo ASUR Marche, Fermo, Italy; Department of Clinical and Molecular Sciences, Polytechnic University of the Marche Region, School of Medicine, Ancona, Italy; Department of Surgery, Cordoba University Medical School, Cordoba, Spain; Department of Pathology and Laboratory Medicine, Indiana University School of Medicine, Indianapolis, IN, USA.
Reference: Int J Immunopathol Pharmacol. 2014 Oct-Dec;27(4):509-16.
PubMed Abstract
PMID: 25572730